https://ar.copernicus.org/articles/ Combined list of the recent articles of the journal Aerosol Research and the recent discussion forum Aerosol Research Discussions en https://doi.org/10.5194/ar-2026-22 Inhalation of small particles (PM2.5) in urban road tunnels and underground Madrid (Spain). A citizen science project Angel Lopez-Encuentra, Esther Gil Cid, and Luis Miguel Pozo Coronado Aerosol Research Discuss., https://doi.org/10.5194/ar-2026-22,2026 Preprint under review for AR (discussion: open, 0 comments) In road tunnels and the metro, there are small toxic airborne particles (PM2.5). In Madrid (Spain), there is no public information on PM2.5 in these infrastructures. One alternative is for citizen scientists to use validated low-cost sensors. Data from these sensors were compared with reference station data; their correlation was high. PM2.5 levels in Madrid’s tunnels and metro exceed 10 µg/m³ and are above the 2011 World Health Organization guideline Fri, 12 Jun 2026 17:23:49 +0200 https://doi.org/10.5194/ar-4-211-2026 Numerical study of the collection of aerosol particles by falling deformable drops Thibaut Ménard, Emmanuel Reyes, Wojciech Aniszewski, Pascal Lemaitre, and Emmanuel Belut Aerosol Research, 4, 211–229, https://doi.org/10.5194/ar-4-211-2026, 2026 This study uses advanced computer simulations to explore how falling water drops remove airborne particles. It shows that, when drops deform and oscillate, their motion strongly affects how efficiently aerosols are captured. The model accurately predicts drop speed and shape, but capture rates can differ from experiments by up to an order of magnitude. These gaps likely stem from missing physical effects (evaporation), uncertainties in aerosol measurements, and numerical inaccuracies. Thu, 11 Jun 2026 17:23:49 +0200 https://doi.org/10.5194/ar-4-231-2026 Assessing the sources of submicron airborne elements at two sites in the Fos-Marseille basin through rolling positive matrix factorization Mathilde Brezins, Benjamin Chazeau, Nicolas Marchand, Amandine Durand, Grégory Gille, Romain Bourjot, Andre S. H. Prévôt, Jean-Luc Jaffrezo, Gaëlle Uzu, and Barbara D'Anna Aerosol Research, 4, 231–254, https://doi.org/10.5194/ar-4-231-2026, 2026 The Marseille–Fos basin faces high anthropogenic pressure from industry and maritime and road transport combined with specific weather conditions that further degrade air quality. Our study focuses on fine metallic pollution, which can penetrate deep into the lungs and cause harmful effects. Using 1 year of measurements at two sites, we identified 10 main pollution sources, half directly linked to human activities, highlighting clear risks for the environment and public health. Thu, 11 Jun 2026 17:23:49 +0200 https://doi.org/10.5194/ar-2026-20 Look−up tables for complex refractive index correction of particle sizes measured by common research−grade optical particle counters Paola Formenti and Claudia Di Biagio Aerosol Research Discuss., https://doi.org/10.5194/ar-2026-20,2026 Preprint under review for AR (discussion: open, 0 comments) This study improves the accuracy of optical particle counters (OPCs), instruments used to measure airborne particles important for air quality and climate research. Because OPC measurements depend not only on particle size but also on composition and shape, results can be uncertain. The paper provides a standardized database of correction factors for five commercial OPCs, helping researchers produce more reliable and consistent aerosol measurements across a wide range of atmospheric conditions. Thu, 11 Jun 2026 17:23:49 +0200 https://doi.org/10.5194/ar-2026-19 In vitro toxicity of CNG exhaust gases and particles generated under varying driving conditions Georgios Tsakonas, Rodopi Stamatiou, Ilias Vouitsis, Athanasios Besis, Athanasios Kouras, Daniel Deloglou, Eleni Papaioannou, Karine Elihn, Constantini Samara, Antigone Lazou, and Zissis Samaras Aerosol Research Discuss., https://doi.org/10.5194/ar-2026-19,2026 Preprint under review for AR (discussion: open, 0 comments) Exhaust from a Euro 6 compressed natural gas taxi was tested under simulated real-world driving, including different driving dynamics and operating conditions. Diluted exhaust was used to expose human lung cells. Although particle mass was low, cell viability was reduced, cell damage was increased, and inflammatory responses were triggered. The findings show that health relevance depends on several emission properties, not particle mass alone. Wed, 03 Jun 2026 17:23:49 +0200 https://doi.org/10.5194/ar-2026-21 The influence of hydrogen addition on carbonaceous aerosols produced by an ethylene flame Stijn S. A. van Rijn, Haiyan Ni, Martijn A. R. Goudberg, Merel R. van Helten, Anatoli Mokhov, and Ulrike Dusek Aerosol Research Discuss., https://doi.org/10.5194/ar-2026-21,2026 Preprint under review for AR (discussion: open, 0 comments) Combusting hydrogen alongside carbon-based fuels has been proposed to reduce CO2 emissions. In this work, we investigate how this affects the emitted particles, using a model flame. Increasing hydrogen leads to smaller particles containing a higher of organic material and less of the of the strongly light absorbing elemental carbon. However, the organic material shows considerable light absorption at shorter visible wavelength and in the UV. Tue, 02 Jun 2026 17:23:49 +0200 https://doi.org/10.5194/ar-4-189-2026 Impact of agricultural interventions on ammonia emissions and on PM2.5 concentrations in the UK: a local and regional modelling study Matthieu Pommier, Robert Benney, Jamie Bost, Becky Jenkins, Joe Richardson, Liam Rock, Olivia Blythe, Oliver Marshall, and Alexandra Spence Aerosol Research, 4, 189–210, https://doi.org/10.5194/ar-4-189-2026, 2026 This study examines NH3 emissions from UK agriculture and the role it plays in PM2.5 formation, focusing on the dairy, pig, and poultry sectors. Using regional and local air quality models, we find that a 13 % NH3 reduction cuts PM2.5 by only ~1 % due to NH3-rich air. The regional model may underestimate PM2.5, while the local modelling shows that emissions disperse within 700 m. The study highlights the value of combining models to better understand the spread of pollutants and to improve PM2.5 control strategies. Thu, 21 May 2026 17:23:49 +0200 https://doi.org/10.5194/ar-2026-14 Co-condensation and co-evaporation of levoglucosan onto and from deliquesced ammonium sulfate particles – influence of relative humidity, particle mass and size, and presence of a surfactant Jian Xu, Junteng Wu, Mayur Gajanan Sapkal, Jim Grisillon, Shravan Deshmukh, Brice Temime Roussel, Julien Kammer, Nicolas Brun, Fabien Robert-Peillard, Beiping Luo, Judith Kleinheins, Silvia Henning, Bénédicte Picquet-Varrault, Edouard Pangui, Mathieu Cazaunau, Zamin A. Kanji, Claudia Marcolli, and Anne Monod Aerosol Research Discuss., https://doi.org/10.5194/ar-2026-14,2026 Preprint under review for AR (discussion: open, 0 comments) The study aimed to mimic the atmospheric behaviour of a semi-volatile organic compound in the presence of fine particles and at various relative humidities. The objective was to determine the influence of organic matter on humid particle growth. These results are essential for improving our understanding of cloud formation. Tue, 05 May 2026 17:23:49 +0200 https://doi.org/10.5194/ar-2026-17 Challenges in measuring sticky biogenic ice-nucleating macromolecules Joseph Robinson, Martin I. Daily, Polly B. Foster, Jack P. Macklin, James B. McQuaid, Mark D. Tarn, and Benjamin J. Murray Aerosol Research Discuss., https://doi.org/10.5194/ar-2026-17,2026 Preprint under review for AR (discussion: open, 0 comments) Ice formation in many clouds is initiated by airborne particles, which are often measured by collecting them on a filter and washing them into water for analysis. Using controlled laboratory experiments, we show that some of these particles adhere strongly to the filter and are not recovered. As a result, this common method can underestimate how many ice-forming particles are present in the atmosphere. Tue, 05 May 2026 17:23:49 +0200 https://doi.org/10.5194/ar-2026-16 Continuous new particle formation in a Mediterranean coastal environment: Insights from atmospheric ions behaviour analysis Nikos Kalivitis, Spyridon-Emmanouil Markoulakis, Panayiotis Kalkavouras, Veli-Matti Kerminen, Markku T. Kulmala, and Maria Kanakidou Aerosol Research Discuss., https://doi.org/10.5194/ar-2026-16,2026 Preprint under review for AR (discussion: open, 0 comments) Atmospheric new particle formation (NPF) is crucial for aerosol number concentration. Recent methodologies propose that “quiet” NPF (QNPF) events, which are not traditionally classified as NPF, can contribute significantly to aerosol number. This study presents three-years of observations of ion and particle size distributions at the Finokalia station in Eastern Mediterranean. It shows that QNPF events are frequent providing fundamentally new understanding of NPF processes in the region. Wed, 22 Apr 2026 17:23:49 +0200 https://doi.org/10.5194/ar-2026-15 Dispersion normalisation method for improved long-term trend evaluation: Heavy Metals in ambient air in the Czech Republic, Central Europe (2010–2021) Adéla Holubová Šmejkalová, Radek Lhotka, Hana Škáchová, and Jan Pacner Aerosol Research Discuss., https://doi.org/10.5194/ar-2026-15,2026 Preprint under review for AR (discussion: final response, 4 comments) This research examined whether legislative measures to reduce heavy metal pollution have been effective in the Czech Republic. We analysed 12 years of data from 16 monitoring stations and used a method that reduces the influence of changing weather. The results showed that this method is suitable for evaluating long-term trends and helps avoid errors in interpreting pollution levels affected by year-to-year weather differences. Mon, 13 Apr 2026 17:23:49 +0200 https://doi.org/10.5194/ar-2026-13 Isomer-resolved online analysis of organic aerosols using ion mobility mass spectrometry Andre F. Schaum, Christopher M. Kenseth, Madison Rutherford, Harald Stark, Manjula R. Canagaratna, Joost A. de Gouw, Jose L. Jimenez, and Kelvin H. Bates Aerosol Research Discuss., https://doi.org/10.5194/ar-2026-13,2026 Preprint under review for AR (discussion: final response, 2 comments) Organic aerosols influence global climate though uncertainties in the magnitude of this influence remain large. A comprehensive understanding of the molecular composition of aerosols is key to minimizing these uncertainties. We present a new method for analyzing organic aerosols in real time using ion mobility mass spectrometry, enabling the separation of aerosol components with identical mass. Analysis of standards and laboratory-generated aerosols demonstrate the method’s potential. Fri, 10 Apr 2026 17:23:49 +0200 https://doi.org/10.5194/ar-4-169-2026 Characterizing aerosol sources based on aerosol optical properties and dispersion modelling in a Scandinavian Coastal Area (Aarhus, Denmark) Zihui Teng, Jane Tygesen Skønager, Andreas Massling, Henrik Skov, Nikolaos Evangeliou, Sabine Eckhardt, Merete Bilde, and Bernadette Rosati Aerosol Research, 4, 169–187, https://doi.org/10.5194/ar-4-169-2026, 2026 Coastal aerosols in Scandinavian urban areas remain understudied. We examined aerosol optical properties and size distributions along Denmark's coastline. Combining in situ data with dispersion modelling, we identified two main aerosol types: carbonaceous aerosols from fossil fuel and biomass burning and large, highly scattering aerosols (potentially sea salt). Black carbon from in situ data and dispersion modelling correlated well, while FLEXPART underestimated the concentration. Wed, 01 Apr 2026 17:23:49 +0200 https://doi.org/10.5194/ar-4-153-2026 Six-year trend of concentrations of ultrafine particles 6 km away from a major German airport Holger Gerwig, Wolfram Birmili, Kay Weinhold, Honey Dawn Contecson Alas, Alfred Wiedensohler, and Wilma Travnicek Aerosol Research, 4, 153–167, https://doi.org/10.5194/ar-4-153-2026, 2026 Seven years of hourly particle number size distributions of 10–500 nanometres were measured at an urban background in Germany. A downward trend of total particle number concentrations of −2 % per year was observed. Wind from the Frankfurt Airport showed the highest nucleation mode particle concentrations. Lockdown lowered the concentration of ultrafine particles in the direction of the airport. On 30 % of all days, the World Health Organization's ultrafine particles value for high concentrations was exceeded. Fri, 20 Mar 2026 17:23:49 +0100 https://doi.org/10.5194/ar-2026-12 Measurements and modeling of urban secondary organic aerosol formation potential as a function of precursor volatility class in the Los Angeles area during summer 2022 Melissa A. Ehrenfels, Benjamin C. Schulze, Andrew R. Jensen, Afsara Tasnia, Douglas A. Day, Pedro Campuzano-Jost, Anne V. Handschy, Melinda K. Schueneman, Seonsik Yun, Dongwook Kim, Donna Sueper, Havala O. T. Pye, Benjamin N. Murphy, T. Nash Skipper, Kelley C. Barsanti, Joost A. de Gouw, and Jose L. Jimenez Aerosol Research Discuss., https://doi.org/10.5194/ar-2026-12,2026 Preprint under review for AR (discussion: open, 0 comments) Los Angeles, CA suffers from poor air quality, partially due to secondary aerosol formation. The identity and sources of the most important gas phase precursors is a complex and unresolved issue. For the first time, we separated ambient gas-phase species by volatility, then measured their potential to form aerosols. We found that higher-volatility emissions are responsible for 2/3 of the aerosol formation, and lower volatility ones for 1/3. We evaluate two box models against our measurements. Fri, 20 Mar 2026 17:23:49 +0100 https://doi.org/10.5194/ar-4-133-2026 Results and insights from the first ACTRIS intercomparison workshop on sub-10 nm aerosol sizing instrumentation Herbert G. Hartl, Janne Lampilahti, Rima Baalbaki, Lauri Ahonen, Tommy Chan, Tinghang Zhang, Joonas Vanhanen, Joonas Purén, Gerhard Steiner, Sebastian Schmitt, Torsten Tritscher, Amine Koched, Manuel Granzin, Petr Roztocil, Silja Häme, Tuukka Petäjä, and Katrianne Lehtipalo Aerosol Research, 4, 133–152, https://doi.org/10.5194/ar-4-133-2026, 2026 Small airborne particles influence how clouds form and how they affect the climate. Our study compared eight different instruments that measure the size distributions of these particles to understand the instruments' strengths and weaknesses. We found that some systems are more accurate, whereas others are more sensitive at tiny sizes. These results will help to improve future monitoring of air quality and climate processes. Wed, 18 Mar 2026 17:23:49 +0100 https://doi.org/10.5194/ar-2026-10 Atmospheric new particle formation enhanced by tricarboxylic acids Astrid Nørskov Pedersen, Yosef Knattrup, and Jonas Elm Aerosol Research Discuss., https://doi.org/10.5194/ar-2026-10,2026 Preprint under review for AR (discussion: final response, 3 comments) We investigated the new particle formation (NPF) potential of three atmospherically relevant oxygenated organic molecules (OOMs) using high-level computational methods. Cluster thermodynamics and formation rates were evaluated for systems containing sulfuric acid and various nitrogen bases. All three OOMs enhanced cluster formation, with dimethylamine-containing clusters showing the greatest effect. PDPE formed the most stable clusters, due to its molecular flexibility. Fri, 13 Mar 2026 17:23:49 +0100 https://doi.org/10.5194/ar-2026-8 Measurements of NaCl in ambient air with a Capture Vaporizer-ToF-ACSM Marije van den Born, Hengjia J. Ou, Jan Mulder, Jinglan Fu, Harald Saathof, and Ulrike Dusek Aerosol Research Discuss., https://doi.org/10.5194/ar-2026-8,2026 Preprint under review for AR (discussion: final response, 2 comments) Sea spray aerosol plays an important role in climate and atmospheric chemistry, yet sea salt is rarely quantified by online mass spectrometers due to its refractory nature. This study shows that a Capture Vaporizer Time-of-Flight Aerosol Chemical Speciation Monitor can detect sea salt aerosol using Na and NaCl fragments. Laboratory and field results demonstrate robust real-time measurements of NaCl surface area, while accurate mass concentrations require particle size information. Tue, 10 Mar 2026 17:23:49 +0100 https://doi.org/10.5194/ar-4-121-2026 Evaluation of mass measurement techniques for soot with different size distributions and OC ∕ TC contents Benoît Sagot, Guillaume Pailloux, and Amel Kort Aerosol Research, 4, 121–131, https://doi.org/10.5194/ar-4-121-2026, 2026 The measurement of particle mass concentrations in gases is essential for monitoring emissions from engine exhaust or atmospheric pollutants. Various instruments allow for real-time concentration monitoring, but few studies have evaluated the accuracy and reliability of these measurements. We present the results of an intercomparison between several mass concentration measurement instruments to assess their ranges of validity, providing valuable guidance for future users of these devices. Tue, 03 Mar 2026 17:23:49 +0100 https://doi.org/10.5194/ar-4-103-2026 Development of the SiMPLE-PAS: a low-cost, three-wavelength photoacoustic spectrometer for aerosol absorption Ashley M. Scott, Charles A. Wise, Ryan P. Poland, Anna D. Jordan, and D. Al Fischer Aerosol Research, 4, 103–120, https://doi.org/10.5194/ar-4-103-2026, 2026 The SiMPLE-PAS is a single-pass, multi-wavelength, portable, and low-expense photoacoustic spectrometer designed to measure absorption of light by atmospheric aerosols. It is differentiated from other PAS instruments by being much less expensive (approximately USD 500 total) and 3D-printed while still allowing measurements at multiple wavelengths. The instrument has competitive detection limits and provides a blueprint for an ultra low-cost PAS to make the technique more accessible. Wed, 25 Feb 2026 17:23:49 +0100